Method of producing compounds of the carnallite type



Patented Aug. 30, 1932 UNITED STATES PATENT oFFice OSCAR KasEmrz, or BERL N, G RMANY METHOD OF PRODUCING COMPOUNDS OF THE QARNAL ITE TYPE No Drawing. Application filed October 18, 1930, Serial No. 489,712, and in Germany November 28, 1929.

.My invention relates toa method of pro ducing compounds of the carnallite type having the formula KCLMgCl +6H2O or NILCLMgCl GH O, hereinafter called potassium carnallite and ammonium. carnallite, respectively. It is one of; the objects Of this invention to provide means whereby these compounds or a mixture thereof can be produced in a simpler and more eflicient manner 1 than was hithertopossible. 7

German Patent No. 391,362 discloses a method of producing anhydrous magnesium chloride from ammonium carnallite by drying this starting material until substantially all the water of crystallization is expelled, and thereafter heating it in a current of evaporated ammonium chloride until the ammonium chloride contained in the carnallite is expelled also. While the residue from this operation consists of substantially anhydrous magnesium chloride, there are obtained vapors of water and ammonium chloride, and these vapors are absorbed by bringing them in contact with a concentrated solution of magnesium chloride, preferably the form of so-called foots, i, e., the usually discarded mother liquors from the manufacture of potassium salts from Stassfurth $fllts.

On cooling the absorption liquor, part of the absorbed ammonium chloride is recovered in the form of fresh amountsof ammonium carnallite, whichmay be reused in the pro duction of anhydrous magnesiumchloride.

A similar method is disclosed in German specification No, 395,510 which describes the production of mixtures of anhydrous magnesium chloride and of potassium chloride such as required in the electrolytic production of metallic magnesium. In accordance with this process potassium carnallite, which may be mixed with ammonium carnallite and/or magnesium chloride and/or alkali chlorides, is heated, preferably after having been mixed with solid ammonium chloride, in a current of ammonium chloride vapors so as to obtain a residue consisting of anhydrous magnesium chloride and alkali chlorides. The carnallites required in this process are obtained from concentrated magnesium chlo- 0 ride solutions, or preferably from foots of the kind aforesaid, by adding hereto potassium chloride or magnesium chloride and allowing-the carnallite to crystallize out.

The question how to utilize the mother liquor resulting in these processes after the ammonium carnallite and the potassium carnal? lite, respectively, have been separated out has not yet been answered although the high price commanded by the ammonium and potassium salts renders a utilization of this mother liq- 6o uor rather important, One might expel the ammonia by heating the mother liquQl With lime, the residual liquors being discarded or the mother liquor might be mixed with solutions of magnesium chloride and ammoni e5 chloride, and evaporated until on cooling fresh amounts of ammonium carnallite crystallize out.

In'contradistinction to this process, which requires heat energy, the present invention affords the means for reutilizing these mother liquors without requiring heating,

According to this invention I mix the mother liquor with the molten magnesium chloride hexahydrate and ammonium chloride; on this mixture cooling down ammonium carnallit-e will crystallize out. Alternatively I cause the mother liquor to react with commercial crystallized magnesium chloride and ammonium chloride to form ammonium carnallit 4 Both products required for these reactions, the molten magnesium chloridehexahydrate as well as the crystallized magnesium chloride, can easily be recovered from the foots of 5 the potassium salt manufacture and can thus be converted in a commercial manner into ammonium carnallite serving for producing anhydrous magnesium chloride. It will be noted that in accordance with my invention the magnesium chloride hexahydrate is used in a crystallized state, be it in the form of solid crystals or in the form of a melt, but at any rate not in solution. I thus avoid the mother liquor being diluted with additional a ounts of ater othe than t of c ystallization as well as an di ional con trating operation necessitated by such an introduction of Water In a similar manner potassium chloride and 400 "crystallized magnesium chloride liexahyuor obtianed. at 25 C. accordingto the proc-- the salt) drate, either molten or solid, can be added to mother liquors containing potassium carnallite or ammonuim carnallite in order to recover potassium carnallite.

A mixture of the two double salts can be obtained in an analogous manner. v

7 Example 1 To 1000 parts by weightof the mother liqess disclosedin German Patent No. 395,510, which contained 87 parts ammonium ch10 ride and 210parts magnesium chloride, 200

parts molten magnesium chloride hexahydrate-having a temperature of 125 C. and 53' parts ammonium chloride were added under stirring. .After cooling down to 25 C 255 parts ammonium carnallite were obtained (apart from the mother liquor adhering to I Exam/plat To 1000 parts of the mother liquor obtained at 25 C; according to the method disclosed in German Patent No. 391,362, were added 200 parts crystallized magnesium chloride hexahydrate and 53 parts ammonium chloride and the' mixture was stirred during one hour. Apart from the mother liquor adhering to thejc'rystals, 248 parts ammonium carnallitei were obtained.

" Wherever the expression crystallized magnesium chloride hexahydrate isused in the claims afiixed'to this specificati'on it is intended to designate the solid crystals or the melt obtained by fusing them, to the excluother modifications thereof and the right to subsequently make claim to any modification not covered bythese claims is expressly reserved. e 7 y l j -1. The method ofproducing a doublejsalt of the carnallite type comprising adding to a mother liquor containing such compound crystallized magnesium chloride hexahydrate and the chloride of the other basic constituent of the double salt, allowing the double salt to crystallize out and reusing the mother 'l liquor. in a fresh operation.

2. "The method of producing a doublesalt basic constituent of the double salt, allowing 1 the double salt to crytallize out and reusing the mother liquor in a fresh operation; 7

3. The method of producing a double salt of the. carnallite type comprising adding to a mother liquor containing such compound solidcrystallized magnesium chloride hexahydrate and the chloride of the other'basic constituent of the double salt, allowing the double salt to crystallize out and reusing the mother liquor in a fresh operation.

4. The method of producing ammonium carnallite comprising "adding to a mother liquor containing ammonium carnal-lite solid crystallized magnesium chloride hexahydrate and ammonium chloride under stirring,-allowing the double salt .to crystallize out and? reusingthe mother liquor in a fresh opera tion. y w a 5. The method of producing ammonium carnallite comprising adding to a mother liquor containing ammonium carnallite crys-E tallized magnesium chloride hexahydrate in,

a molten'state and ammonium chloride under stirring, allowing the double salt to crystallize out and reusing the motherliquor-in a fresh operation:

' 6."The method of producing ammoniumcarnallitecomprising adding to a mother liquor containing ammonium carnallite solid crystallizedmagnesium chloride hexahydrate and ammonium chloride under stirring, al-' lowing the-double salt to crystallize out and reusing the mother liquor in a fresh operation. Y "7. The method of producing potassium carnallite comprising adding to a mother liquor containing potassium carnallite crystallized'magnesium chloride hexahydrate in a molten'state and potassium chloride under stirring, allowing the double salt to crystallize'out and reusing the mother liquor in a fresh operation. r 8. The meth d of producing potassium carnallite comprising adding to a mother liquor containing potassium carnallite cryspotassium chloride-under stirring, "allowing the double'salt tocrystallize out and reusing the mother liquor in a fresh op eration.,- I

9. The method of producingfpotassium carnallite comprising adding to a mother tallized magnesium chloride hexahydrate and liquor containing potassium carnallite solid I crystallized magnesium chloride hexahydrate andpotassium chloride under stirring, allow:

ing the double salt to crystallize out and reusing the'mother liquor ina fresh operation; In testimonywhereofl aflix my signature. OSCAR KASELITZ.

of. the carnallite type comprising adding to a mother liquor containing such compound crystallized magnesium chloride hexahydrate' v in a molten state and the chloride'of the other 

